I took the solid cover off our pool today and noticed the water level had dropped about 3 inches since closing it 6 months ago. I'm pretty sure there's a leak somewhere since it hasn't dropped like this before. I have a couple ideas where the leak may be, but it would require I get in and it's too cold right now (I replaced a couple of rings/seals that seal the liner around the returns last season....perhaps this is where the leak is?). It's entirely possible that it may have been leaking during last season but I didn't notice it since its so slow.

Is this something I should be concerned about now? I'm thinking because its so slow ( .5" per month) I can just keep an eye on it for now.

What do our experts here think?